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1
Content available High quality repetitive control system for a grid-tied converter under distorted grid voltage conditions – design and implementation
Ufnalski Bartlomiej, Straś Andrzej, Grzesiak Lech M.
Bulletin of the Polish Academy of Sciences. Technical Sciences
|
2021
|
Vol. 69, nr 2
art. no. e136739
EN
The paper features a grid-tied converter with a repetitive current controller. Our goal here is to demonstrate the complete design workflow for a repetitive controller, including phase lead, filtering and conditional learning. All key parameters, i.e., controller gain, filter and fractional phase lead, are designed in a single optimization procedure, which is a novel approach. The description of the design and optimization process, as well as experimental verification of the entire control system, are the most important contributions of the paper. Additionally, one more novelty in the context of power converters is verified in the physical system – a conditional learning algorithm to improve transient states to abrupt reference and disturbance changes. The resulting control system is tested experimentally in a 10 kW converter.
2
Content available Variable-structure repetitive control for discrete-time linear systems with multiple-period exogenous signals
Kurniawan Edi, Harno Hendra G., Wijonarko Sensus, Widiyatmoko Bambang, Bayuwati Dwi, Purwowibowo Purwowibowo, Maftukhah Tatik
International Journal of Applied Mathematics and Computer Science
|
2020
|
Vol. 30, no. 2
207--218
EN
A new method to construct a discrete-time variable-structure repetitive controller for a class of linear systems perturbed by multiple-period exogenous signals is presented. The proposed control scheme combines the features of the discrete-time multiple-period repetitive control (MP-RC) and variable-structure control (VSC) techniques. The MP-RC part is assigned to simultaneously track and reject periodic signals consisting of multiple uncorrelated fundamental frequencies. The VSC part is then integrated to provide a fast transient response and robustness against plant parameter variations. Stability and robustness analyses are also elaborated to ensure that the resulting closed-loop system satisfies the desired control objectives. Moreover, it is shown through an example that the repetitive control system constructed using the proposed control method can effectively track a sinusoidal reference signal despite the presence of a multiple-period disturbance.
3
Content available remote On the similarity and challenges of multiresonant and iterative learning current controllers for grid converters and why the disturbance feedforward matters
Ufnalski B., Grzesiak L M., Kaszewski A., Galecki A.
Przegląd Elektrotechniczny
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2018
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R. 94, nr 5
38--46
EN
There are two main techniques to solve the reference tracking problem for repetitive references and under repetitive disturbances, namely multiresonant (a.k.a. multioscillatory) controllers and iterative learning controllers. Nevertheless, neither of the approaches is a definitive winner, which is to be demonstrated herein. Both have their strengths, weaknesses and challenges. A grid-tie converter will be the case study here. The goal is to draw or inject sinusoidal currents under distorted grid voltage conditions. The supporting feedforward controller will be addressed within the context of the discussed repetitive control task. The case will be illustrated using numerical simulations. Our main goal is to make practitioners familiar with the relationships between these two control methods.
PL
Istnieją dwia główne sposoby rozwiązywania zadania regulacji nadążnej dla powtarzalnego sygnału zadanego w obecności powtarzalnego zakłócenia, jest to zastosowanie regulatorów wielorezonansowych (zwanych też wielooscylacyjnymi) oraz regulatorów z uczeniem iteracyjnym. Jednak żadnego z tych rozwiązań nie można uznać za jednoznacznie lepsze, co zostanie tutaj pokazane. Oba cechują zarówno mocne strony, jak i pewne słabci oraz wyzwania implementacyjne. Przekształtnik sieciowy posłuży tutaj za przykład. Celem jest pobieranie lub oddawanie sinusoidalnego prądu sieci pomimo odkształconego napięcia. Omówione zostanie również sprzężenie w przód od zakłócenia w kontekście zadania sterowania powtarzalnego. Zagadnienie zostanie zilustrowane przy użyciu symulacji komputerowych. Naszym głównym celem jest pokazanie praktykom związków pomiędzy tymi dwiema metodami sterowania.
4
Content available Robust aperiodic-disturbance rejection in an uncertain modified repetitive-control system
Zhou L., She J., Li C., Pan C.
International Journal of Applied Mathematics and Computer Science
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2016
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Vol. 26, no. 2
285--295
EN
This paper concerns the problem of designing an EID-based robust output-feedback modified repetitive-control system (ROFMRCS) that provides satisfactory aperiodic-disturbance rejection performance for a class of plants with time-varying structured uncertainties. An equivalent-input-disturbance (EID) estimator is added to the ROFMRCS that estimates the influences of all types of disturbances and compensates them. A continuous-discrete two-dimensional model is built to describe the EID-based ROFMRCS that accurately presents the features of repetitive control, thereby enabling the control and learning actions to be preferentially adjusted. A robust stability condition for the closed-loop system is given in terms of a linear matrix inequality. It yields the parameters of the repetitive controller, the output-feedback controller, and the EID-estimator. Finally, a numerical example demonstrates the validity of the method.
5
Content available Repetitive neurocontroller with disturbance feedforward path active in the pass-to-pass direction for a VSI inverter with an output LC filter
Ufnalski B., Grzesiak L. M.
Bulletin of the Polish Academy of Sciences. Technical Sciences
|
2016
|
Vol. 64, nr 1
115--125
EN
An enhancement to the previously developed repetitive neurocontroller (RNC) is discussed and investigated in the paper. Originally, the time-base generator (TBG) has been used to produce the only input signal for the neural approximator. The resulting search space makes the dynamic optimization problem (DOP) of shaping the control signal solvable with the help of a function approximator such as the feed-forward neural network (FFNN). The plant under consideration, i.e. a constant-amplitude constant-frequency voltage-source inverter (CACF VSI) with an output LC filter, is assumed to be equipped with the disturbance load current sensor to enable implementation of the disturbance feed-forward (pDFF) path as a part of the non-repetitive subsystem acting in the along the pass p-direction. An investigation has been undertaken to explore potential benefits of using this signal also as an additional input for the RNC to augment the approximation space and potentially enhance the convergence rate of the real-time search process. It is numerically demonstrated in the paper that the disturbance feed-forward path active in the pass-to-pass k-direction (kDFF) improves the dynamics of the repetitive part as well indeed.
6
Content available A 2D system approach to the design of a robust modified repetitive-control system with a dynamic output-feedback controller
Zhou L., She J., Zhou S.
International Journal of Applied Mathematics and Computer Science
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2014
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Vol. 24, no. 2
325--334
EN
This paper is concerned with the problem of designing a robust modified repetitive-control system with a dynamic output feedback controller for a class of strictly proper plants. Employing the continuous lifting technique, a continuous-discrete two-dimensional (2D) model is built that accurately describes the features of repetitive control. The 2D control input contains the direct sum of the effects of control and learning, which allows us to adjust control and learning preferentially. The singular-value decomposition of the output matrix and Lyapunov stability theory are used to derive an asymptotic stability condition based on a Linear Matrix Inequality (LMI). Two tuning parameters in the LMI manipulate the preferential adjustment of control and learning. A numerical example illustrates the tuning procedure and demonstrates the effectiveness of the method.
7
Content available remote DSP Based Hardware Implementation of Repetitive Current Controller for Interleaved Grid Connected Inverter
Jamil M., Sharief F., Yasin A., Ahmed A., Gulfam S. M., Khaqan A., Riaz R. A.
Przegląd Elektrotechniczny
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2013
|
R. 89, nr 2a
251-255
EN
The performance of the repetitive controller (RC) for classical inverters (e.g. two-level LCL filter based inverter) can decline if the system bandwidth is not sufficient enough due to much larger LCL filter component values. The novel interleaved inverters can provide higher bandwidth than the classical inverters because of low filter values. This paper reflects upon the analysis and hardware implementation of the RC for interleaved inverter using DSP. High quality (very low THD) output current is demonstrated through simulation and experimental results.
PL
W artykule przedstawiono analizę i implementację na DSP sterowania powtarzalnego dla badanego falownika typu interleaved. Przedstawione wyniki badań symulacyjnych, pokazują wysoką jakość (niskie THD) prądu wyjściowego przekształtnika.
8
Content available remote Artificial neural network based voltage controller for the single phase true sine wave inverter – a repetitive control approach
Ufnalski B., Grzesiak L.M.
Przegląd Elektrotechniczny
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2013
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R. 89, nr 4
14-18
EN
The paper presents novel error backpropagation based neurocontroller for true sine wave inverter. The controller is trained in on-line mode. Adaptation algorithm takes into account repetitiveness of the process to be controlled. The cost function evaluates performance of the controller over the whole period of the reference signal and the weights are updated only once a period of this signal. A model-free concept is employed and hence no neural (or of any other type) model of the plant is needed. Proposed topology does not limit its area of implementation to the discussed converter. The controller is capable to maintain a high-quality output voltage waveform in the presence of periodic disturbance caused by nonlinear loads.
PL
W artykule przedstawiono metodę budowy neuronowego regulatora napięcia dla falownika o sinusoidalnym napięciu wyjściowym. Regulator uczony jest w trybie on-line. Algorytm adaptacji wag sieci uwzględnia powtarzalność procesu poprzez odpowiednią definicję funkcji celu oraz uaktualnianie wag sieci raz na okres sygnału zadanego. Synteza układu regulacji nie wymaga identyfikowania modelu obiektu (podejście typu model-free). Zaproponowana topologia regulatora umożliwia jego wykorzystanie również do sterowania innymi procesami powtarzalnymi. Regulator pozwala na utrzymanie wysokiej jakości napięcia wyjściowego również dla okresowych obciążeń nieliniowych.
9
Content available remote A Novel Control Strategy for the Power Supply to Achieve the A Novel Control Strategy for the Power Supply to Achieve theA Novel Control Strategy for the Power Supply to Achieve the A Novel Control Strategy for the Power Supply to Achieve the 45 T / 600
Liu W., Ding H., Duan X., Li L., Herlach F.
Przegląd Elektrotechniczny
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2011
|
R. 87, nr 11
285-289
EN
In order to achieve the 45 T / 600 ms flat-top field, one type of high-field quasi-continuous magnets (HFQCM) and a power supply system related are now under construction at the Wuhan National High Magnetic Field Center (WHMFC). Considering the temperature rise of the magnet and ripple minimization, the topology and the novel repetitive control method of the power supply system is detailed. Simulated results are provided to validate the proposed method.
PL
Aby wytworzyć pole magnetyczne 45 T/600 ms opracowano specjalny typ układu zasilającego. Uwzględniono ryzyko wzrostu temperatury i potrzebę minimalizacji zafalowań.
10
Content available remote Voltage/current control mode for combined three-phase inverter
Wang H., Yue X., Pei X., Kang Y.
Przegląd Elektrotechniczny
|
2010
|
R. 86, nr 11a
358-362
EN
For parallel inverters system, controlling the output voltage in normal operation constantly is named the voltage control mode (VCM), and controlling the output current constantly in abnormal operation conditions (such as short circuit) is named the current control mode (CCM). The combined three-phase inverter topology is presented, the equivalent inverter topology with a LCL filter is obtained and mathematical models are built in VCM and CCM. A hybrid control strategy is proposed. The PID control and the repetitive control are used in VCM to obtain the fast dynamic responses and low harmonic distortions. On the other hand, the state feedback control is used in CCM. Pole assignment has been employed in designing parameter of the PID controller and state feedback, and the repetitive control design process is given. Experimental results validate the proposed control using two 400KVA parallel inverters.
PL
Dla równoległego systemu przekształtników zazwyczaj stosuje się system kontroli napięcia VCM i system kontroli prądu CCM (w warunkach specjalnych - np. zwarcia). Zaprezentowano topologie przekształtnika trójfazowego. Odpowiednia topologia przekształtnika z filtrem LCL została przedstawiona. Zaproponowano hybrydową strategię sterowania. System PID sterowania użyty w VCM zapewnia szybką odpowiedź dynamiczną i małe zniekształcenia. W układzie CCM użyto stałego sprzężenia zwrotnego. Sprawdzono położenie biegunów. Wyniki eksperymentu z dwoma 400kVA równoległymi przekształtnikami potwierdziły założenia.
11
Content available remote Analiza możliwości redukcji zniekształceń napięcia wyjściowego 3-fazowych inwerterów napięcia dla nieliniowego obciążenia prostownikowego
Rymarski Z.
Przegląd Elektrotechniczny
|
2009
|
R. 85, nr 4
127-132
PL
Artykuł przedstawia analizę możliwości redukcji zniekształceń napięcia wyjściowego 3-fazowych inwerterów napięcia dla typowego nieliniowego obciążenia prostownikowego typu RC. Wykazano, że nie zawsze jest możliwe efektywne obniżenie tych zniekształceń dla wybranego punktu pracy inwertera, bez względu na rodzaj stosowanego sprzężenia zwrotnego. Przedstawiono prostą, ale pozwalającą uzyskać akceptowalne zniekształcenia napięcia wyjściowego, metodę całościowego, równoczesnego projektowania 3-fazowego stopnia mocy i dyskretnego regulatora.
EN
This paper presents an analysis of distortion reduction of the 3-phase VSI output voltage for a typical nonlinear load - the rectifier RC load. It is shown that effectively lowering distortions is not always possible for the chosen operating point of the inverter, no matter what control loop is used. A simple but effective design method of the 3-phase VSI power stage and the discrete control loop is presented.
12
Content available remote System Identification from Multiple-Trial Data Corrupted by Non-Repeating Periodic Disturbances
Phan M. Q., Longman R. W., Lee S. C., Lee J. W.
International Journal of Applied Mathematics and Computer Science
|
2003
|
Vol. 13, no 2
185-192
EN
Iterative learning and repetitive control aim to eliminate the effect of unwanted disturbances over repeated trials or cycles. The disturbance-free system model, if known, can be used in a model-based iterative learning or repetitive control system to eliminate the unwanted disturbances. In the case of periodic disturbances, although the unknown disturbance frequencies may be the same from trial to trial, the disturbance amplitudes, phases, and biases do not necessarily repeat. Furthermore, the system may not return to the same initial state at the end of each trial before starting the next trial. In spite of these constraints, this paper shows how to identify the system disturbance-free dynamics from disturbance-corrupted input-output data collected over multiple trials without having to measure the disturbances directly. The system disturbance-free model can then be used to identify the disturbances as well, for use in learning or repetitive control. This paper represents the first extension of the interaction matrix approach to the multiple-trial environment of iterative learning control.
13
Content available remote Comparison of the Stability Boundary and the Frequency Response Stability Condition in Learning and Repetitive Control
Songschon S., Longman R. W.
International Journal of Applied Mathematics and Computer Science
|
2003
|
Vol. 13, no 2
169-177
EN
In iterative learning control (ILC) and in repetitive control (RC) one is interested in convergence to zero tracking error as the repetitions of the command or the periods in the command progress. A condition based on steady state frequency response modeling is often used, but it does not represent the true stability boundary for convergence. In this paper we show how this useful condition differs from the true stability boundary in ILC and RC, and show that in applications of RC the distinction between these conditions is of no practical significance. In ILC satisfying this frequency condition is important for good learning transients, even though the true stability boundary is very different.
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